Here is another video. If you are trying to replace a zipper in pants, this one is what you want. It actually shows a pair of pants she has made, but it should be the same way for replacing a zipper, I guess :0) I love it. I don't know if I want to try it, but this is just what I have wanted to know.
This is part 1 by the way, be sure to check out part 2 also.